1. Field of the Invention
This invention relates to a miniature camera module with a lens containing an image sensor such as a charge coupled device (CCD) or a CMOS sensor.
2. Description of the Related Art
Recently, there has been developed a miniature camera module with a lens containing an image sensor such as a CCD or a CMOS sensor (e.g., refer to Jpn. Pat. Appln. KOKAI Publication No. 2004-88181). The miniature camera module is incorporated in a mobile telephone, a portable information terminal or the like and thus commercialized.
The miniature camera module generally has, on an image sensor, a filter such as a cover glass or an infrared rays (IR) cut filter, or an optical low pass filter. This filter serves to seal a space over the image sensor and reduce defects due to dust produced in the second half of an assembly process, and to achieve natural color reproducibility by use of a non-reflective coat or an infrared rays cut coat deposited on the cover glass.
One problem heretofore associated with such a filter is defects due to moving dirt produced after the assembly. This is a problem in which even if a product is judged as nondefective in a test before shipment, dust present in the tube moves to an effective area during transportation or during use in the market to cause defects such as dark flaws or stains. The source of such moving dirt includes, for example, chippings of the IR cut filter, the seepage of an adhesive used when bonding the IR cut filter to a base, or dust produced from a screw portion when a lens barrel is moved.